Microfluidics is a rapidly growing field allowing exploratory research in both chemistry and biology. An essential requirement for microfluidic devices is the ability to selectively move a desired fluid from one place to another. To accomplish this, numerous microfluidic pumps and valves have been previously developed. These valves operate on a variety of principles and include pneumatic, thermal, piezoelectric, magnetic, and mechanically actuated valves (Oh et al., A Review of Microvalves, Journal of Micromechanics & Microengineering, 16, R13-R39, 2006; Iverson et al., Recent Advances in Microscale Pumping Technologies: A Review and Evaluation, Microfluidics & Nanofluidics, 5, 145-174, 2008; Gervais et al., Microfluidic Chips for Point-of-Care Immunodiagnostics, Advanced Materials, 23, H151-H176, 2011). The mechanism of action of these valves involves an elastomeric or other interface material between the selected input, unselected inputs, and common output. Existing valves have significant limitations, including switching speed, dead space, undesired fluid mixing, failure, difficulty integrating with microfluidic devices, and cost (Melin et al., Microfluidic Large-Scale Integration, Annual Review of Biophysics & Biomolecular Structure, 36, 213-231, 2007).
While previous membrane-compression valves require piezoelectric or electromagnetic actuators, solenoid valves, or pneumatic controllers, this valve design is highly advantageous because it relies on only a rotating drivehead and mechanical support. This drivehead can either be rotated by a simple DC motor, or for manual operation, the DC motor could be replaced with a simple knob or lever. Other manual or motorized rotary compression valves that utilize a screw to clamp a channel closed (e.g., Hulme et al., Incorporation of Prefabricated Screw, Pneumatic, and Solenoid Valves into Microfluidic Devices, Lab on a Chip, 9, 79-86, 2009; Weibel et al., Torque-Actuated Valves for Microfluidics, Analytical Chemistry, 77, 4726-4733; Markov et al., Tape Underlayment Rotary-Node (TURN) Valves for Simple On-Chip Microfluidic Flow Control, Biomedical Microdevices, 12, 135-144, 2010) are not readily capable of switching between multiple inputs and multiple outputs because only one channel is compressed directly at a time.
The classic pneumatically activated microfluidic valve (e.g., Unger et al., Monolithic Microfabricated Valves and Pumps by Multilayer Soft Lithography, Science, 288, 113-116, 2000) requires continuous application of pressure to keep the valve closed, and the valve must be connected to a solenoid valve controller. Braille actuators can be used to close an elastomeric membrane valve (e.g., Gu et al., Computerized Microfluidic Cell Culture Using Elastomeric Channels and Braille Displays, Proceedings of the National Academy of Sciences, 101, 15861-15866, 2004), but power must be delivered continuously to the Braille actuator to keep the valve closed. PDMS and hybrid PDMS-glass normally closed valves have been created (e.g., Grover et al., Monolithic Membrane Valves and Diaphragm Pumps for Practical Large-Scale Integration into Glass Microfluidic Devices, Sensors & Actuators B, 89, 315-323, 2003; Lagally et al., Integrated Portable Genetic Analysis Microsystem for Pathogen/Infectious Disease Detection, Analytical Chemistry, 76, 3162-3170, 2004; Schudel et al., Microfluidic Chip for Combinatorial Mixing and Screening of Assays, Lab on a Chip, 9, 1676-1680, 2009; Song et al., Computer-Controlled Microcirculatory Support System for Endothelial Cell Culture and Shearing, Analytical Chemistry, 77, 3993-3999, 2005; Zhang et al., PMMA/PDMS Valves and Pumps for Disposable Microfluidics, Lab on a Chip, 9, 3088-3094, 2009), but as with other pneumatic valves, each valve must be connected to tubing and a solenoid valve, and a source of either pressure or vacuum is required to operate each valve. Whether such membrane valves are either normally open or normally closed, pressure, force, or power must be provided to keep the valve in the opposite state. Furthermore, these pressure-activated diaphragm valves are not readily suited for multi-port, multi-throw interconnection of multiple input and output channels without the use of a large number of coordinated pressure or vacuum controllers.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.